Influência do manejo em arroz irrigado nas propriedades físicas do solo e na produtividade de grãos

Abstract

The Rio Grande do Sul State is the greater producer of flooded rice from Brazil, highlighting the west border region. The objective of this work was to evaluate soil physical properties and flooded rice yield in different systems. The work was carried out in the 2009/2010 and 2010/2011 seasons with experimental design completely randomized with three experiments (E) and ten replicates. In 2009/2010 season the following experiments had been carried out: E1, no-tillage after leveling (E1PDR) and conventional tillage with two harrowings at 0.0-7 cm layer after leveling (E1C), after seven years of fallow of rice tillage, with sowing of rye grass in winter and grazing; E2, no-tillage(E2PD) and conventional tillage (E2C), after native filed; E3, no-tillage (E3PD), no-tillage after leveling (E3PDR), and conventional tillage (E3C) after rice under no-tillage, during one year under native field. In 2010/2011season the experiments were: E1, no-tillage (E1PD) and conventional tillage with two harrowings at 0.0-7 cm layer after leveling (E1C), in area of one year of rice culture after seven years of fallow of rice tillage, with sowing of rye grass in winter and grazing; E2, no-tillage (E2PD) and conventional tillage (E2C), after native filed; E3, no-tillage (E3PD), and conventional tillage (E3C) after rice under no-tillage, during two year under native field. It was evaluated soil density, total porosity, aggregates stability, macro and microporosity, dry mass in soil surface and rice grains yield. In no- tillage soil physical properties are similar to the conventional tillage. The flooded rice yield did not differ between the no-tillage system and conventional tillage.